cv2.imshow() crashes Kernel

Question

I am running OpenCV through Jupyter Notebooks and whenever I try to run cv2.imshow() the kernel crashes, no error message or helpful hint - just a plain

The Kernel appears to have died. It will restart automatically.

Here is the code I am running...

import cv2 
input = cv2.imread('images/input.jpg')
cv2.imshow('Hello World', input)
cv2.waitKey(0)
cv2.destroyAllWindows()

The code works (albeit differently) when I run the below...

%matplotlib inline
from matplotlib import pyplot as plt
import cv2
image = cv2.imread('images/input.jpg')
plt.imshow(image)
plt.show()

FYI I am using a completely unaltered copy of BitFusion on AWS.

https://aws.amazon.com/marketplace/pp/B01EYKBEQ0?ref=cns_srchrow

Any idea what could be going wrong?

Solution 1

I can't explain the behavior of your code right now but you can use the below code to achieve the above behavior.

%matplotlib inline
from matplotlib import pyplot as plt
import cv2
image = cv2.imread('images/input.jpg')
plt.imshow(image)
plt.show()

Solution 2

To view images with cv2.imshow on AWS, you need to enable X11 forwarding so the graphics can be run on the server and displayed locally. This can be done by ssh-ing with the -Y option:

ssh -Y username@hostname

If the images are larger, you will also need to compress the data using -C:

ssh -Y -C username@hostname

The terminal used to ssh into AWS will need to be left open as long as you're displaying images from the notebook.